# US 11,122,101 B2 · Method and apparatus to encode and decode two-dimension point clouds > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,101 B2 - Document ID: US11122101B2 - Status: Granted - Kind: B2 - Application number: 15/969,009 - Filed: 2018-05-02 - Published: 2018-11-08 - Granted: 2021-09-14 - Earliest claimed: 2017-05-04 - Assignees: InterDigital VC Holdings, Inc. - Applicants: THOMSON Licensing - Inventors: Julien Fleureau; Bertrand Chupeau; Renaud Dore - Web page: https://patentgrep.com/patent/US11122101B2 ## CPC - H04L 65/70: Media network packetisation - G06T 3/06: Topological mapping of higher dimensional structures onto lower dimensional surfaces - G06T 9/001: {Model-based coding, e.g. wire frame} - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N 19/85: using pre-processing or post-processing specially adapted for video compression - H04N 19/90: using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The present disclosure relates to methods, devices or streams for encoding, transmitting and decoding two-dimension point clouds. When encoding point clouds as frames, a large number of pixels are not used. A dense mapping operator optimizes the use of pixels but requires a lot of data to be encoded in the stream and its inverse operator is difficult to compute. A simplified mapping operator is generated according to a dense mapping operator and is stored as matrices of two-dimension coordinates representative of an unfolded grid which requires low space in the stream. The inverse operator is easy to generate according to the unfolded grid. ## Claims ### Claim 1 A method of decoding a two-dimension point cloud from a bit stream, said method comprising: obtaining, from the bit stream, a frame of pixels and a matrix of two-dimension coordinates in said frame representative of an unfolded grid, said matrix being obtained by mapping a regular grid according to a dense mapping operator that decreases the number of unused pixels of the frame for said two-dimension point cloud; determining an un-mapping operator as a piecewise bilinear interpolator parametrized with said matrix; and decoding the two-dimension point cloud by applying said un-mapping operator to said frame. ### Claim 2 (depends on 1) The method of claim 1, wherein the matrix is associated with a group of frames in the bit stream, the method further comprising decoding frames of said group of frames by applying the un-mapping operator determined according to said matrix to said frames. ### Claim 3 A method of encoding a two-dimension point cloud in a bit stream, the method comprising: generating a matrix of two-dimension coordinates representative of an unfolded grid by mapping a regular grid according to a dense mapping operator, the dense mapping operator being a mapping operator decreasing the number of unused pixels of a second frame of pixels encoding said two-dimension point cloud; generating a first frame of pixels by applying a mapping operator to said two-dimension point cloud, said mapping operator being determined as a piecewise bilinear interpolator parametrized with said matrix; and generating the bit stream by encoding said first frame associated with said matrix of two-dimension coordinates representative of said unfolded grid in the bit stream. ### Claim 4 (depends on 3) The method of claim 3, wherein the dense mapping operator is determined for a group of two-dimension point clouds, and further comprising generating a frame for each point cloud of said group of two-dimension point clouds and associating said matrix with the generated group of frames in the bit stream. ### Claim 5 (depends on 3) The method of claim 3, wherein the two-dimension point cloud is a projection of a n-dimension point cloud on a surface, n being greater than two. ### Claim 6 A device comprising a memory associated with at least one processor configured to: obtain, from a bit stream, a frame of pixels and a matrix of two-dimension coordinates in said frame representative of an unfolded grid, said matrix being obtained by mapping a regular grid according to a dense mapping operator that decreases the number of unused pixels of the frame for said two-dimension point cloud; determine an un-mapping operator as a piecewise bilinear interpolator parametrized with said matrix; and decode the two-dimension point cloud by applying said un-mapping operator to said frame. ### Claim 7 (depends on 6) The device of claim 6, wherein the matrix is associated with a group of frames in the bit stream, and wherein said at least one processor is further configured to decode frames of said group of frames by applying the un-mapping operator determined according to said matrix to said frames. ### Claim 8 A device comprising a memory associated with at least one processor configured to: generate a matrix of two-dimension coordinates representative of an unfolded grid by mapping a regular grid according to a dense mapping operator; the dense mapping operator being a mapping operator decreasing the number of unused pixels of a second frame of pixels encoding said two-dimension point cloud; generate a first frame of pixels by applying a mapping operator to said two-dimension point cloud, said mapping operator being determined as a piecewise bilinear interpolation parametrized with said matrix; and generate a bit stream by encoding said first frame associated with said matrix in the bit stream. ### Claim 9 (depends on 8) The device of claim 8, wherein the dense mapping operator is determined for a group of two-dimension point clouds, and wherein said at least one processor is further configured to generate a frame for each point cloud of said group of two-dimension point clouds and to associate said matrix with the generated group of frames in the bit stream. ### Claim 10 (depends on 8) The device of claim 8, wherein the two-dimension point cloud is a projection of a n-dimension point cloud on a surface, n being greater than two. ### Claim 11 A non-transitory medium storing data representative of a two-dimension point cloud, wherein the data comprises: a matrix of two-dimension coordinates representative of an unfolded grid generated by mapping a regular grid according to a dense mapping operator, the dense mapping operator being a mapping operator decreasing the number of unused pixels of a frame for said two-dimension point cloud; and a first frame of pixels generated by applying a mapping operator to a second frame of pixels encoding the two-dimension point cloud, said mapping operator being determined as a piecewise bilinear interpolation parametrized with said matrix, wherein the matrix is associated with said frame.